[Port to 2.3-develop] Add trim filter to first, middle and lastname.

[wardcapp]

A similar pull request was set up before (see #12964) and has now, with this PR, been ported to the 2.3-develop branch as well.

Description

The additional trim form field data filter was created and added as
input filter to the firstname, lastname and middlename fields
of the customer_address and customer entities.

Fixed Issues (if relevant)

1. Customer First and Last names not being trimmed of leading and trailing spaces on save. #10415: Customer First and Last names not being trimmed of leading and trailing spaces on save.

Manual testing scenarios

1. Create a new customer from the Customers > All Customers > Create New Customer window
2. Create First name: "John " Last name: " Doe ", add a fake email address.
3. Click save
4. Search and edit the contact "John Doe "
5. Take note that the spaces are no longer in the users first, middle and last names. Same goes for the customer names set on the customer addresses.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[wardcapp]

Hi @mzeis, you've probably already noticed, but I just committed your patch from PR #12964 to this one as well, meaning both are holding the same changes now.

[mzeis]

Hi @wardcapp, thanks for your contribution. It has been merged into 2.3-develop!